Soil solution pH values beneath the oak canopy were approximately 0.5-1.0 unit higher than comparable horizons of grassland soils. It appears that increased base cation cycling by oak is responsible for enriching the base status of the oak canopy soils resulting in the elevated pH values. Partial neutralization of precipitation acidity by the canopy may also contribute to the higher pH values. Soil solution pH values showed a decrease of approximately 0.25 units following oak tree removal. The pH values of soil solutions in the cut plots were midway between those of oak canopy and grassland plots. This rapid shift in soil solution pH was unexpected since these soils have a strong buffering capacity that should resist large fluctuations in solution pH. Leaching of base cations coupled with the lack of partial neutralization of precipitation acidity by canopy processes may contribute to this rapid decrease in pH.